1. Field of the Invention
The present invention relates to a recording medium conveying system which serves to transfer such optical recording media as a compact-disk and a mini-disk, such magnetic recording media as a floppy disk, and such storage type recording media as a RAM card to a loading section (recording/reproducing section) and to return them from the loading section.
2. Description of the Prior Art
FIG. 15 is a side elevational view schematically showing a construction of a general recording medium conveying system for selecting recording media 1, and further for loading them in a loading section. The recording media 1 are, for example, a mini-disk acting as a recording medium which is housed in a disk cartridge. The recording media 1 are inserted in an X1 direction from the left-hand side in the illustration into a plurality of receiving areas which are vertically arranged in a housing section 2. At the right-hand side in the illustration there is situated a loading unit 5 including a loading section 3 and a holding member 4 which moves upwardly and downwardly in Y1 and Y2 directions and stops at a position that allows the selection of one of the recording media 1. Between the housing section 2 and the holding member 4 there are placed a transferring roller 6 rotationally driven reversibly (forward and backward) and a supporting roller 7 positioned in opposed relation to the transferring roller 6.
FIG. 15 shows the loading unit 5 selecting the recording medium 1 present in the uppermost receiving area of the housing section 2. The uppermost recording medium 1 is pushed out of the receiving area through a mechanism, not shown, and is interposed between the transferring roller 6 and the supporting roller 7. Subsequently, the recording medium 1 moves in the X1 direction due to the rotating force of the transferring roller 6 and is received within the holding member 4. Then, the holding member 4 moves downward in the Y2 direction to mount the recording medium 1 on the loading section 3. More specifically, the central portion of the mini-disk housed in the cartridge is mounted on a turntable 8 situated on the loading section 3. Further, the mini-disk, together with the turntable 8, is driven rotationally so that the recorded signal is read out through an optical head, not shown.
Upon completion of the read-out from the recording medium 1, the holding member 4 moves in the Y1 direction to separate the recording medium 1 from the loading section 3. Thereafter, the recording medium 1 within the holding member 4 is moved slightly in an X2 direction by means of a mechanism, not shown, such that it is interposed between the transferring roller 6 and the supporting roller 7, and then returned to a vacant receiving area of the housing section 2.
However, the following problems arise when, as shown in FIG. 15, the recording medium 1 is transferred using the transferring roller 6.
1) In order to reliably transfer the recording medium 1 in the X1 or X2 directions between the transferring roller 6 and the supporting roller 7, the transferring roller 6 and the supporting roller 7 need to hold or grasp the recording medium 1 with a strong holding force. An insufficient holding force can cause the transferring roller 6 to slip on the recording medium 1 surface, thereby failing to transfer the recording medium 1 in the X1 and X2 directions. Accordingly, the transferring roller 6 is required to be pressed toward the supporting roller 7 with a strong holding force to some extent by a biasing means such as a spring. However, the aforesaid holding force due to the pressing operation can resist separation of the rollers 6 and 7 such that the recording medium 1 is prevented from being received between the rollers 6 and 7. This resistance increases as the thickness of the recording medium 1 increases. Therefore, when the recording medium 1 is fed or supplied from the station housing 2 between the rollers 6 and 7 by means of a mechanism (not shown), a considerably strong force is needed for feeding the recording medium 1 in the X1 direction, with the result that for transferring the recording medium 1 in the X1 direction it is necessary to use a significant amount of power and a mechanism, such as a lever, having great strength. This also applies to the case where the recording medium 1 held in the holding member 4 is fed between the rollers 6 and 7 by means of another mechanism (not shown). In this case, if the recording medium 1 is forcibly pressed between the rollers 6 and 7 with great power, there is a possibility that the recording medium may be broken.
2) In the example shown in FIG. 15, after the recording medium 1 is fed by the transferring roller 6 and the supporting roller 7 in X1 direction, the recording medium 1 needs to be further drawn into the holding member 4 through a mechanism (not shown). In this case, if the recording medium 1 is pulled into the holding member 4 while being held between the transferring roller 6 and the supporting roller 7, because of the feeding force by the transferring roller 6 in the X1 direction is still applied to the recording medium 1, if there is a difference between the speed at which the recording medium 1 is fed by the transferring roller 6 in the X1 direction and the speed at which it is drawn by the unshown mechanism in the X1 direction, this speed difference causes the application of a large load to the unshown mechanism, which may cause the unshown mechanism to separate from the recording medium 1.
3) The aforesaid problems are not limited to the case where the recording medium 1 is transferred from the housing section 1 to the rollers 6 and 7. These problems also apply to the case where the recording medium 1 is inserted between the rollers 6 and 7 by hand. That is, if the recording medium 1 is manually inserted, the resistance of the rollers 6 and 7 to the insertion of the recording medium 1 is extremely great, thereby producing a sense of incongruity on operation.
4) FIG. 16 is an illustration of the state that a mini-disk or the like, being one example of the recording medium 1, is accommodated within a cartridge 1a. The cartridge 1a has a window formed in its upper surface to allow access to the mini-disk, and includes a shutter Id which freely slides relative to the cartridge 1a in the same direction as the cartridge 1a feeding direction (the X1-X2 directions). When this kind of recording medium 1 is used, a shutter opening mechanism is provided which opens the shutter id prior to loading the recording medium 1 into the loading section 3. Further, during ejection of the recording medium 1 from the loading section 3 after the completion of recording or reproduction, the shutter 1d returns to the original closing condition. When the recording medium shown in FIG. 16 is transferred in the X1 or X2 direction while being held between the transferring roller 6 and the supporting roller 7, the transferring roller 6 strikes against the movable shutter 1d, thereby making it difficult to apply a uniform feeding force from the transferring roller 6 to the recording medium 1 across its entire width, with the result that the recording medium 1 does not move smoothly. In addition, there is a possibility that, when the recording medium 1 is fed by the transferring roller 6, the shutter 1d unintentionally slides in its opening direction due to the rotating force of the transferring roller 6. For instance, if the shutter 1d opens while the recording medium 1 is fed in the X1 direction, the relative positions of the shutter 1d and the shutter opening and closing mechanism, which operates after transfer, can vary, such that closure of the shutter 1d becomes difficult when the recording medium 1 is discharged from the loading section 3.